title: Comparative study of the influence of 3 types of mineral water in patients with idiopathic calcium lithiasis.
abstract: OBJECTIVE
  While there is general agreement on the need to increase urinary volume in stone formers, contrasting opinions have been expressed about the hardness of water and stone incidence. We evaluate the influence of 3 types of mineral water on urinary analytes in 22 idiopathic calcium oxalate stone formers.
  
  
  METHODS
  All patients underwent a nutritional and metabolic evaluation at baseline, and after a controlled diet including water with a high, medium or low calcium content.
  
  
  RESULTS
  In patients who drank water with high and medium calcium contents calcium excretion increased, although the results did not reach statistical significance. In those who drank water with the highest calcium content oxalate excretion significantly decreased (p = 0.05), as did the oxalate-to-calcium ratio (p = 0.05). Moreover, these modifications did not induce relevant changes in urinary saturation. In patients who drank water with the greatest amount of bicarbonate citrate excretion increased (p = 0.03).
  
  
  CONCLUSIONS
  Mineral water with a higher calcium content induced increased calcium excretion but significantly decreased oxalate excretion. These data are in accordance with those of others, who did not find definite evidence that hard water is more lithogenic than soft water. Furthermore, water components other than calcium can modify the tendency toward crystal formation, affecting inhibitory power and/or lithogenic salt excretion.
authors.affiliation: Dipartimento di Medicina Clinica e Biotecnologia Applicata D. Campanacci, Universitá degli Studi, Bologna, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Caudarella
authors.forename: E
authors.initials: E
authors.lastname: Rizzoli
authors.forename: A
authors.initials: A
authors.lastname: Buffa
authors.forename: A
authors.initials: A
authors.lastname: Bottura
authors.forename: S
authors.initials: S
authors.lastname: Stefoni
mesh_terms: D000328:Adult; D002118:Calcium / Q000032:analysis / Q000378:metabolism* / Q000652:urine; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000378:metabolism* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D008900:Mineral Waters / Q000032:analysis; D010070:Oxalates / Q000652:urine; D012307:Risk Factors
chemical_list: D008900:Mineral Waters; D010070:Oxalates; D002118:Calcium